The present invention relates to methods for the benefaction, gasification and liquefaction of coal and other carbonaceous materials. The fuel materials contemplated include anthracite, bituminous and lignite coal along with other materials such as wood,, lignin, oil shale, tar sand, peat, solid petroleum residuals and various solid products derived from coal and other carbonaceous materials.
Previous methods for carrying out the processing of solid carbonaceous materials have employed solid catalysts of cobalt, iron, nickel, molybdenum and alloys such as cobalt-molybdenum. Since the coal or other carbonaceous material is also in solid form, it is difficult to obtain contact between the solid phases and the other reactants. Consequently, high temperatures have been used to break carbon to carbon bonds for hydrogen addition. This hydrogenolysis of the carbonaceous substrate can produce gaseous and liquid products.
In processes for the liquefaction of coal with a solid catalyst, organic liquids, often recycled product, are used as a media for catalyst-reactant contact. Hence these processes are characterized as heterogeneous catalytic reactions employing heterogeneous catalysts.
Various processes as the Bureau of Mines synthoil and others employ heterogeneous catalytic reactions in which hydrogen is reacted with materials within the coal at temperatures above about 400.degree. C. and pressures of 100-250 atmospheres. These reaction conditions promote hydrogenolysis in which carbon to carbon bonds are broken and hydrogen is added. In addition, other atoms such as oxygen, nitrogen and sulfur found in the carbonaceous materials are converted to water, ammonia and hydrogen sulfide. To the extent that these reactions remove sulfur and other pollutants, they can be desirable but otherwise they can be a nonproductive consumption of hydrogen.